PLT OF EXPERIMENTAL SEAPLANE BUCCANEER MAKES A TKOF AND BARELY CLBS ABOVE TREES.

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ON DEP FROM THE STEINHATCHEE RIVER THE ACFT CAME WITHIN 10 OR 20 FT OF IMPACTING TREES. I HAD FLOWN THE ACFT INTO THE RIVER LOCATION ON THE PREVIOUS DAY. IN OBSERVING THE AREA BEFORE LNDG THERE APPEARED TO BE MORE THAN SUFFICIENT AREA FOR A NORMAL LNDG AND DEP. LNDG WAS UNEVENTFUL. LATER THE SAME DAY I DEPARTED FOR A SHORT TRIP TO OBTAIN FUEL. THE ACFT WAS LIGHT AND WITH A STIFF BREEZE THE DEP WAS NORMAL. I WAS; HOWEVER; UNCOMFORTABLE WITH THE CLRNC OF THE ACFT OVER TALL TREES AT A BEND IN THE RIVER. I DECIDED AT THE TIME I WOULD DEPART NEXT TIME WITHOUT MY PAX AND PICK HER UP AT A LOCATION WITHOUT DEP OBSTRUCTIONS. THE NEXT MORNING WAS CALM; CLR; AND COOLER THAN THE PREVIOUS DAY. BECAUSE ARRANGEMENTS TO TAKE THE PAX TO ANOTHER LOCATION WOULD HAVE INCONVENIENCED OUR FRIENDS AND DELAYED OUR DEP; I DECIDED TO DEPART WITH BOTH OF US ONBOARD. I TAXIED TO THE MOST UPSTREAM PORTION OF THE RIVER. THE ACFT SEEMED TO OPERATE NORMALLY BUT THE TKOF RUN WAS LONGER THAN I EXPECTED. AT THE POINT OF LIFT-OFF I STILL EXPECTED TO HAVE SUFFICIENT PERFORMANCE TO CLR THE TREES. THE CLB RATE WAS EXTREMELY POOR. I MAINTAINED 20 DEGS OF FLAPS FOR MAX CLB RATE. IT QUICKLY BECAME OBVIOUS I WOULD NOT CLR THE CLOSEST TREES. I WAS ABLE TO BANK SUFFICIENTLY TO FOLLOW THE RIVER AND GAIN ADDITIONAL TIME FOR CLBING. THIS REQUIRED BANK ANGLES AT LOW SPD; CLOSE TO THE RIVER. ULTIMATELY THE RIVER COURSE BECAME IMPOSSIBLE TO FOLLOW AND I HAD NO CHOICE BUT TO TRY AND CLR THE TREES. THE AIRPLANE HAD CLBED SUFFICIENTLY TO CLR THE TREES BY ABOUT 10 FT TO 20 FT. THE REMAINDER OF THE CLBOUT WAS SLOW; BUT UNREMARKABLE. THE KIT BUILT ACFT DOES NOT HAVE AN OPERATING MANUAL. IT IS A 2-PLACE AMPHIBIAN WITH A LISTED MAX GROSS WT OF 1175 LBS. EMPTY WT IS 575 LBS; OR 650 LBS WITH FULL FUEL. A PAX REPRESENTS A SIGNIFICANT PERCENTAGE OF GROSS WT AND GREATLY DEGRADES ACFT PERFORMANCE. BASED ON OTHER ACFT I HAVE ALWAYS ASSUMED THAT 20 DEGS OF FLAP WOULD GIVE THE BEST ANGLE OF CLB. TYPICALLY; HOWEVER; I USE 20 DEGS TO GET OFF THE WATER AND 10 DEGS TO CLB. I'M NOT CERTAIN THAT 20 DEGS PROVIDES THE BEST PERFORMANCE UNDER THE CIRCUMSTANCES. CONTRIBUTING FACTORS: 1) THE AIRPLANE WAS AT MAX GROSS WT; 2) THE WIND CONDITIONS WERE CALM AS COMPARED TO THE PREVIOUS DAY; 3) I DID NOT WANT TO DELAY THE DEP AND ENCOUNTER INCREASED AIR TEMPS; INCREASED RIVER ACTIVITY; AND INCONVENIENCE OUR FRIENDS; 4) FAILURE TO TEST THE MAX CLB PERFORMANCE OF THE ACFT IN SAFER CONDITIONS; 5) AN OPTIMISTIC ASSESSMENT OF CLB PERFORMANCE WITH 20 DEGS OF FLAPS AT MAX GROSS WT; AND 6) NO CLRLY ESTABLISHED GO/NO-GO POINT. I'VE READ MANY ACCIDENT RPTS AND THOUGHT I WAS NOT SUSCEPTIBLE TO THE ERRORS OF JUDGEMENT THAT COULD HAVE RESULTED IN AN ACCIDENT IN THIS CASE. IN RETROSPECT I SHOULD HAVE STUCK WITH THE DECISION TO DEPART BY MYSELF AT A LOW GROSS WT. AN ALTERNATIVE WOULD HAVE BEEN TO TAXI TO A BETTER DEP AREA. I UNDERESTIMATED MY SUSCEPTIBILITY TO EXTERNAL INFLUENCES (FRIENDS; CONVENIENCE). I OVERESTIMATED THE ACFT AND PLT CAPABILITIES. AS CORRECTIVE ACTION A CHKLIST WHICH INCLUDES CONSIDERATION OF THE CONSEQUENCES OF AN ERRONEOUS ESTIMATE COULD MAKE THE MORE CONSERVATIVE DECISION EASIER. THE ACFT PERFORMANCE WILL BE CHKED UNDER CTLED CONDITIONS AND A SAFETY FACTOR APPLIED FOR FUTURE OPS.